Light sensitive layer and process of preparing it



Patented Sept. 16, 1930 PATENT OFFICE eu's'rav xoanL, or KARLSRUHE, GERMANY LIGHT SENSITIVE LAYER AND PROCESS OF PREPARING IT No Drawing. Application filed December 4, 1928, Serial No. 323,801, and in Germany December 13, 192 7.

The present invention relates to the preparation of light-sensitive layers by means of ferric salts.

I have found that light-sensitive layers 6 suitable for copying a positive from a negative can be obtained by means of ferric salts, the process being carried out by mixing the ferric salts with ketones which, when exposed to light, yield color com- 10 pounds.

For the preparation of the layer there is used as first component a ferriccompound, such' as ferric ammonium citrate ferric am monium tartrate, ferric-ammonium oxalate or the like; also ferric chloride and ferric sulfate mixed with each other.

As second component-there are used ketones which are capable of combining with ferrous salts so as to form color compounds.

. Among those compounds quinones are particularly suitable in the new process, for mstance beta-naphthoquinonesulfonic acid, nitroso compounds, or isonitroso compounds of beta-carbonyl compounds of an aliphatic, aromatic, or aliphatic-aromatic character.

The above mentioned ferric compounds are reduced to ferrous compounds on exposure to light andform, on being coupled with the second component, directly VlSlbl6' coloring matter.

There may be added to the layer some binding material,.such as gelatin or. starch; also metallic salts which are'suitable for reducing the solubility of the dyestufis, and

any additional mordant. If. a silver compound is addedto the layer, copies of the type of the so-called Sep 1a'paper are obtamed. p v By the new process it is possible to obtain pictures which exhibit the. greater part of the coloration already during the copying operation, so that the washing-and developing operations only serve to complete the 5 coloration and to. remove the surplus of the chemical substances.

The following example serves to illustrate my invention but is not intended to .limit it thereto: mixture of 1 part of ferric ammonium citrate with-3 parts of isonitrosoacetylacetone and some hydrolyzed starch and barium chloride added thereto is applied on paper. After the layer has been dried, it

is exposed to light under a. pattern. The

picture is immediately produced whereuponit is treated with water. In the same manner may be used isonitrosopropionylacetone, also-nitroso-beta-naphthol or the like. When using beta-naphtholquinone-4-sulfonic acid, pictures with a more greenish tone are obtained. If the pictures require to be mordanted subsequently, this can be done by means of a bichromate or the like.

I claim: 1. The process of preparing light-sensitive layers, suitable for taking a positive from a negative, by means of a ferric salt, which process consists in combining a ferric salt with a compound of the'following formula:

' omcocacox wherein X stands for alkyl,

2. The rocess of preparing light-sensitive layers, sultable for taking a positive from a. negative, by means of ferric ammonium citrate, which process consists in combining said ferric ammonium citrate with .a compound of the following formula:

2 omcocacocm 3. Light-sensitive layers, suitable for takmg of a rric salt and. a compound of the following formula:

wherein X stands for alkyl,

4. Light-sensitive layers, suitable for taking a ositive from a negative, which consist of a of the following formula:

'5. The process of preparing light-sensitive a fpositive from a negative, which consist 61110 ammonium citrate and a comlayers, suitable for t'aking a positive from 1 a negative, by means of a ferric salt, which process consists in combining a ferric salt with a compound selected from the groupconsisting of beta-naphth0quinone1sulfonic 5 acid, isonitrosoaceyl-acetone, isom'trosopropionyl-acetone and nitroso-beta-naphthol. V

6. The process of preparing light-sensitive layers, suitable for taking a positive froma negative, by means of ferric ammonium 10 citrate, which process consists in combining said ferric ammonium citrate with a com-' pound selected from the cup consisting of beta-naphthoquinone-sul onic acid, isonitrosoacetyl-acetone, isonitrosopropion-yl-acetone:

15 and nitroso-beta-naphthol.

7. Light-sensitive layers, suitable for tak ing a positive from a negative, which consist of a ferric salt and a compound selected from the group consisting of beta naphthoquinone- 2Q sulfonic acid, isonitrosoacetyl-acetone, isonitrosopro io-nyI-acetone and nitroso-beta.- naphthofi 8. Light-sensitive layers, "suitable for taking a sitive from a negative, which consist of a errie ammonium citrate and a com- .ound selected from the up consisting of I eta-'naphthoquinone-sul a rfic acid, isonitrosoacetyI-acetone, isonitrosopfopionyl-acetone and nitroso-beta-naphthol.

a In testimony whereof, I aflix my signature.

GUSTAV KOGEL. 

